This grant proposal reflects a strong desire by a group of 20 NIH funded investigators at Brigham and Women's Hospital to establish a state-of- the-art-Gel Scanning facility containing a Molecular Dynamics PhosphorImager. The PhosphorImager uses innovative storage phosphor technology to accurately quantitate 32P, 14C, 35S, 125I, X-ray and gamma ray radiation. This quantitation is far superior to that obtained using standard autoradiographic techniques due to the enhanced sensitivity, expanded range of linearity, and quantitative reproducibility of the PhosphorImager. brigham and Women's Hospital does not posses an instrument capable of detecting radiation by phosphor storage technology. The gel scanning facility will be located in the Longwood Medical Research Center which is a newly constructed 100,000 square foot research facility. This location is easily accessible to the entire research community at Brigham and Women's Hospital. We anticipate that the PhosphorImager will be able to effectively serve both the 20 researchers submitting this proposal as well as a substantial number of additional Brigham and Women's Hospital investigators. The establishment of a State-of-the art gel scanning facility will markedly enhance the sensitivity, resolution and accuracy of quantitative gel analysis at the Brigham and Women's Hospital.